Association Of Circulating-Free Dna Mutation With Response Of Targeted Therapy In Her2-Positive Metastatic Breast Cancer.

e12083Background: The addition of anti-HER2 targeted drug, like trastuzumab, lapatinib and TDM-1, to chemotherapy significantly improved prognosis of HER-2 positive breast cancer patients. However, it was confused that metastatic patients vary in the response of targeted drug. Therefore, methods of accurately predicting drug response were really needed. Because of the spatial and temporal limitations of needle core biopsies, we aimed to developing a higher sensitive and less invasive method of detecting mutations associated with drug response via circulating-free DNA (cfDNA) as a “liquid biopsy”. Methods: We developed a panel for detection of hotspot mutations from 50 oncogenes and tumor suppressor genes in 24 plasma samples of HER2-positive metastatic breast cancer patients who received systemic therapy from March 2014 to October 2015. Results: Totally 486 single nucleotide variants (SNV) from 46 genes were detected from 24 plasma samples. All samples harboured at least one mutation in this 50 genes pane...